Parametric Analysis on the Vibration Characteristics of Sandwich composites Structure (original) (raw)
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Composite sandwich structures composed of a metal foam core possess the ability to provide significant energy absorption under impact from flying debris, routine operation, tool drop, flying projectiles, or crash conditions. Sandwich constructions of aluminum foam core and a variety of facesheets are being increasingly used in a number of applications ranging from turbine shrouds, heat exchangers, pneumatic tool mufflers, energy absorbers for blast shock waves, and silencers for jet engine intakes. In the present work, vacuum assisted resin transfer molding (VARTM) was used to produce composite sandwich plates with laminate facesheets and aluminum foam core. Aluminum foam of two different thicknesses and densities were studied in conjunction with facesheets composed of either S2-glass, E-glass, aramid, or carbon fiber reinforced vinyl ester (VE) resin. Low velocity impact (LVI), up to 5 m/s, and intermediate velocity impact (IVI), up to 100 m/s, tests were conducted to simulate impact conditions resulting from tool drop to blunt objects, and flying debris. It was concluded from the impact tests that the sandwich construction with S2-glass/VE facesheets in conjunction with aluminum foam was optimal for resisting low and intermediate velocity impact. The vibration response of composite sandwich plates composed of laminate facesheets and aluminum foam core was also studied under a free-free boundary condition. The vibration response (natural frequency and damping ratio) is reported as a function of impact to the sandwich plate.
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Natural fibers due to their low cost, high specific strength, recyclability, and environmental friendliness, are finding increasing applications in automotive, aerospace, bio-medical, and sports equipment. In the present work, hybrid sandwich composites using Jute and Glass fibers in Polyester polymer, namely: Jute-Glass-Jute (JGJ) and Glass-Jute-Glass (GJG), were prepared by curing under pressure using compression moulding technique. The prepared sandwich composites were subjected to tensile and flexural testing. Their vibration and damping characteristics were studied using free vibration and forced vibration test rigs. Further, the influence of using Magneto Rheological (MR) fluid on vibration damping properties of the composite samples have also been investigated. The tensile and flexural strengths of GJG composites were found to be higher than that of JGJ and plain jute composites. In terms of their free vibration response, JGJ composites showed slightly higher natural frequenc...
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Sandwich composites and syntactic foams independently have been used in many engineering applications. However, there has been minimal effort towards taking advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of structures. To that end, the goal of this study is to investigate the mechanical response and damage mechanisms associated with syntactic foam core sandwich composites subjected to dynamic impact loading. In particular, this study investigates the influence of varying cenosphere volume fraction in syntactic foam core sandwich composites subjected to varying dynamic impact loading and further elucidates the extent and diversity of corresponding damage mechanisms. The syntactic foam cores are first fabricated using epoxy resin as the matrix and cenospheres as the reinforcement with four cenosphere volume fractions of 0% (pure epoxy), 20%, 40%, and 60%. The sandwich composite panels are th...
The estimation of static and eigenvibration properties of honeycomb sandwich reinforced by polymeric foam were investigated in the paper. A new ''real microstructure " numerical 3D FEM model was proposed for the analysis in which the face materials and the honeycomb were modelled by shell elements, whereas filling foam was modelled by solid elements. Two variants of the honeycomb sandwich panel were considered: with and without polymer foam filling. Static and modal analyses have been performed in both, filled and hollow cases, to observe the effect of core stabilization with foam, particularly for higher natural frequencies. The effective properties of the honeycomb sandwich panels were estimated for both considered cases. Similar calculations have been made for the core materials without top and bottom faces and for the sandwich plate without honeycomb core structure (only polymer foam). One can observe: (1) the substantial increase of the effective elastic properties of the plate; (2) that the eigenvibration properties depend strongly on: the face material, honeycomb core and filling materials properties. The above conclusions are important for design process of structural parts. Crown
Mechanical behaviour of a syntactic foam/glass fibre composite sandwich: experimental results
Structural Engineering and Mechanics, 2001
This note presents the main results of an experimental investigation into the mechanical behaviour of a composite sandwich conceived as a lightweight material for naval engineering applications. The sandwich structure is formed by a three-dimensional glass fibre/polymer matrix fabric with transverse piles interconnecting the skins; the core is filled with a polymer matrix/glass microspheres syntactic foam; additional Glass Fibre Reinforced Plastics extra-skins are laminated on the external facings of the filled fabric. The main features of the experimental tests on syntactic foam, skins and sandwich panels are presented and discussed, with focus on both in-plane and out-of-plane responses. This work is part of a broader research investigation aimed at a complete characterisation, both experimental and numerical, of the complex mechanical behaviour of this composite sandwich.